Burglar-alarm



R. M. CAMPBELL.

Burglar Alarm.

`Patented March 8, 1859.

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UNITED STATES PATENT OFFICE.

ROBERT M. CAMPBELL, OF EAST CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO\VILLIAM G. CROMBIE, OF BOSTON, MASSACHUSETTS.

BURGLAR-ALARM.

Specification of Letters Patent No. 23,215, dated March 8, 1859.

To all whom it may concern:

Be it known that I, ROBERT M. CAMPBELL, of East Cambridge, in the countyof Middlesex and State of Massachusetts, have in vented an ImprovedBurglar-Alarm; and I do hereby declare that the same is fully describedand represented in the following specification and the accompanying'drawings, of which- Figure l, denotes a top view, Fig. 2, a frontelevation; Fig. 3, a rear elevation; Fig. A, a vertical and transversesection; and Fig. 5, a front end elevation of the same.

My invention is intended to be applied to a door and its casing and soas to operate, when an attempt is made to open the door, as to cause theexplosion of a percussion cap and thereby sound an alarm by which aperson within an apartment provided with such door may be informed of anattempt being made to enter the said apartment or to open its door.

In the drawings, A, denotes a circular box or case, of what may betermed a percussion lock. vWithin the said case there is a percussion,hammer or striker, B, and a nipple or percussion cap receiver', C, thehammer being forced toward the same by means of a spring, D.

A spring catch or trigger E is arranged within the case, and in front ofthe forward end of the hammer and is made to project a short distancerearward through the case, its upper end being furnished with a knob, a.This spring catch or trigger is constructed with a notch or recess, Z),to receive a stud, c, projecting from the front end of th-e hammer, thereception taking place, when the hammer is cocked or after being raisedto full cock, and such parts serving to maintain the striker at cock.

A sliding fastener, G, is applied to the percussion alarm lock in suchmanner not only to be capable of being slid or moved fronrthecircumference toward the side of the case, A, and vice versa, but ofbeing folded down flatwise upon the case, as well as of being opened atright angles thereto. To this end, the fastener G is applied to a bar orplate, H, affixed to the rear side of the case A, or arranged thereon,as shown .in the drawings, such bar being made to extend through anopening (I, made through the fastener Gr. such fastener being secured inthe plate H, by ahinge pin, c,

which passes downward through the fastener and in rear of the part H,and so as to enable the fastener not only to be slid or moved on thesaid part H, but of being either turned down parallel to the case A, orat right angles thereto as before mentioned.

The fastener, G, consists of two spring plates f, g, arranged withrespect to one another as shown in the drawings, or it may be a rigidplate having a spring applied to it and in such manner that when the twoare within the joint or space between the edge of a door and its casing,the spring by resting or pressing against-the door shall force the platein close Contact with the door casin g, that side of the fastener whichis in contact with the casing being furnished with teeth or spurs L, L,to enter the same. The rear of the case A, is furnished with a smallturning catch or button, z', applied in such manner as to be capable ofbeing turned over upon the fastener, G, so as to hold it in place, whenit is laid down flatwise upon its case.

In the application of the above described alarm apparatus to a door andits casing, after the nipple C, has been provided with a percussion cap,and the hammer B, has been cocked, the sliding fastener G, is to bemoved outward to the outer edge of the case A, and arranged to projectat, or about atV a right angle thereto. In this position of thefastener, Gr, its inner surface or its spring should be placed againstthe inner edge of the door casing and the door should be afterwardclosed upon the fastener so as to secure .it firmly within the jointbetween the edge of the door and its casing. This having beenaccomplished, the case, A, should be moved forward in such manner as tocarry the fastener toward the middle of the case, and cause the case tolap over both door and case, and in such manner that the knob, a, shallcome directly in front of the door. Under this state of the parts,should an attempt be made to open the door, it will press against theknob a, and in consequence of the case A being firmly held in positionby the fastener, G, and the door casing, the trigger catch E, will bemoved so as to discharge the hammer or striker and permit its spring tothrow it down upon the percussion cap and effect the explosion of thesame, the noise of which will produce the necessary alarm. Furthermorethe case and sliderserve as a look to prevent the door from being openeduntil the Case may be moved laterally.

5 I do not claim a percussion alarm, a gimlet or any such means offastening the same to a door casing; but

hat I do claim is- The application of the spring Jfastener G,

to the alarm or its ease so as to be capable 10 of sliding,` and turningWith reference to the same substantially in manner as specified.

In testimony whereof, I have hereunto set my signature.

R. M. CAMPBELL.4 '1i Witnesses:

R. H. EDDY, F. P. HALE, Jr.

